1. Field of the Invention
The present invention is directed to an optical connector.
2. Related Art
Mechanical optical fiber connectors for the telecommunications industry are known. For example, LC, ST, FC, and SC optical connectors are widely used.
However, commercially available optical connectors are not well suited for outside plant field installations. Typically, an adhesive is required to mount these types of ferrule-based connectors on to an optical fiber. The process of bonding the fiber to the ferrule can be awkward and time consuming to perform in the field. Also post-assembly polishing requires that the craftsman have a higher degree of skill.
Remote grip optical fiber connectors are also known, such as those described in U.S. Pat. Nos. 5,337,390 and 7,775,726. These connectors employ a mechanical gripping element to secure the optical fiber as opposed to an adhesive.
Also known are hybrid optical splice connectors, as described in JP Patent No. 3445479, JP Application No. 2004-210251 (WO 2006/019516) and JP Application No. 2004-210357 (WO 2006/019515). However, these hybrid splice connectors are not compatible with standard connector formats and require significant piecewise assembly of the connector in the field. The handling and orientation of multiple small pieces of the connector can result in incorrect connector assembly that may either result in decreased performance or increase the chance of damaging the fiber.
Also known are connectors that incorporate fiber stubs that are factory installed. In these connectors, the back end of the stub fiber is mechanically spliced to a field fiber, where an index matching gel is used to fill the gap between the back end of the fiber stub and the front end of the terminated fiber. For outdoor applications, especially for environments that can undergo a wide temperature variation, the index of refraction of the gel may change as a function of temperature leading to more reflections, thus limiting the connector performance in those particular applications.
Another effect that can occur is movement of the fiber ends relative to each other, caused by differential thermal expansion over the temperature range. For ferrules with stubs bonded in place, if the fiber protrusion from the ferrule end is too great, excessive forces can be applied to the fiber end when mated with another connector, which can fracture the bond line and cause mating failure.